Bundling strap



S. J. KOHKE BUNDLING STRAP Jan. 13, 1970 Filed Aug. 22, 1968 INVENTOR. STEPHEN J. KOHKE BY I A TTORNEY United States Patent US. CI. 24-16 9 Claims ABSTRACT OF THE DISCLOSURE The disclosure is directed to a bundling strap for forming a plurality of discrete articles into a unitary bundle. The strap is given increased pull-out strength by the inclusion of a novel enlargement within the transverse aperture of the strap head end portion which provides a limitation upon the flexure of the locking means within the head end aperture and thereby prevents withdrawal of the strap from the aperture within the head end portion. Additional strength is achieved by providing an undercut directly ahead of the enlargement within the head end aperture and by providing support means to back up the locking means. The combined eflects of the enlargement, the undercut and the backup of the locking means act to deform the strap Within the head end aperture in such a manner as will provide maximum locking and resistance to the pull-out of the strap from within the head end aperture.

BACKGROUND OF THE INVENTION Field of the invention The invention is directed to the field of bundling discrete articles into a bundle and finds particular utility for bundling individual conductors into a cable. In a similar manner the device may be employed for the bundling to gether into unitary form, a plurality of discrete articles such as rods, tubes, hose, etc.

Description of the prior art Prior art cable bundling straps of the type described herein are shown in the patent to D. -P. Schwester et al., Patent No. 3,186,047, issued June 1, 1965 and owned by the assignee of the instant invention. Straps of the type shown in the Schwester patent have elongated body portions having a tapered tail end portion and a head end portion. A one way locking means is provided in an aperture within the head end portion through which the tail end portion may be threaded and drawn tightly about a plurality of articles to be bundled. Attempts to remove the articles, or to loosen the strap after the strap has been tightened about the bundle, result in deflection of the looking means in a direction not desired. Further, as a result of the attempt to withdraw the strap certain deformation of the head will take place which will permit the locking means to now swing in the undesired direction releasing locking engagement with the bundle strap and permitting the strap to be withdrawn.

SUMMARY OF THE INVENTION The present invention overcomes the difficulties noted above with respect to the Schwester et a1. device. This is achieved by strengthening the head of the cable bundling strap to offset any effects of the deformance of the head and to cause the continued restriction of the movement of the locking device, whereby engagement between the locking device and the strap will not be terminated despite deformance of the cable bundling 'strap head portion. This desirable result is achieved by the inclusion of an enlargement within the head end aperture appended to the upper aperture defining surface. The enlargement is mounted adjacent the entry portion of the head end aperture and ice extends for a portion of the total head end aperture length. An undercut is positioned adjacent the enlargement, removedfrom the entry point, and a backup support is provided behind the locking means to further limit its movement in the direction of pull-out. Attempts to withdraw the strap from the head end aperture will result in the slight deformance of the locking means and will cause the strap body portions to be jammed along the undercut portion and against the enlargement whereby a great degree of the deformance of the head end aperture is permitted while retaining the locking engagement between the locking means and the strap in the head end aperture. The enlargement will be contoured at the entry point to minimize the interference between the strap and the enlargement during the insertion of the strap within the head end portion. Further, the enlargment will be contoured so that no undue stress is created within the strap body itself as it traverses the path along the undercut and the enlargement. It is therefore an object of this invention to provide an improved self clinching bundling strap with increased pull-out strength.

It is yet another object of this invention to provide an improved self clinching bundling strap having an en largement within the head end aperture to limit the degree of flexure, in the pull-out direction, of the locking means of the bundling strap.

It is yet another object of this invention to provide an improved cable bundling strap having both an enlarge ment and an undercut area preceding the enlargement permitting the strap portion to follow the undercut and the enlargement and limit the degree of movement of the locking means within the head end aperture of the strap.

It is still another object of this invention to provide an improved cable bundling strap having a backup means for the locking means of a cable bundling strap, which operating in conjunction with the enlargement, within an enlargement and an undercut portion of the upper head aperture defining surface, limits the movement of the locking means in the pull-out direction.

Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention, and the best mode which has been contemplated for carrying it out.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side elevation of a cable bundling strap constructed in accordance with the concepts of the invention shown in dashed line in its nonbundled condition and shown in solid line bundled about a plurality of articles.

FIG. 2 is a side elevation of a head end portion, partly in section, of a prior art bundling strap as shown in the Schwester et al. patent.

FIG. 3 is a side elevation of the head end portion, partially in section, of a bundling strap constructed in 'accordance with the concepts of the invention.

FIG. 4 is a side elevation of a head end portion, partly in section, of the instant device showing the relative positions of the bundling strap body and locking means with respect to the head end aperture during attempted withdrawal of the body portion of the strap from the head end portion.

Similar elements will be given similar reference characters in each of the respective figures.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to FIG. 1 there is shown a bundling strap 10 constructed in accordance with the concepts of the invention. Bundling strap has a tapered tail end portion 12 and a head end portion 14 with a body portion 16 extending therebetween. In order to employ the bundling strap 10 to hold a plurality of discrete articles such as the conductors 18 into a cable, the tapered tail end portion 12 of the strap 10 will be wrapped about said conductors 18 and positioned through the transverse aperture extending through the head end portion 14. The tapered tail end section 12 will be drawn by the use of fingers, or an appropriate tool, in order to tightly draw the strap body portion 16 about the plurality of articles 18.

Turning now to FIG. 2 there is shown the head end portion of the self clinching bundling strap as is shown in the Schwester et al. patent. Within the head end portion 14 there exists a transverse aperture 20 extending from a rear face 22 to a front face 24. Mounted Within a cavity 26, defined by the horizontal surface 28 and the vertical surface 30, is positioned a metallic tongue 32. Metallic tongue 32 has a first end 34 embedded within the material of the head end portion 14 and a knife edge 36 which extends within the aperture 20 of the head end portion 14. When the body portion 16, of the bundling strap 10, is inserted within the aperture 20 of the head end portion 14 from face 22 towards the face 24, metallic tongue 32 will deflect to the right of the figure permitting relatively free entry of the body portion 16 into the head end aperture 20. Attempts to withdraw the body portion 16 of the strap 10 will result in knife edge 36, of the metallic tongue 32, biting into the material of the body portion 16 to restrain its withdrawal. However, the continued application of force, attempting to pull the body portion 16 of the strap 10 towards the left of the figure, will result in the deforming of the head end portion 16 enlarging aperture 20 and will permit the rotation of the knife edge 36 of the metallic tongue 32 in a direction towards the face 22 allowing the withdrawal of the strap body portion 16.

In order to overcome this difiiculty, the head end portion 14 of the instant invention modifies the upper aperture defining surface 40 and the lower aperture defining surface 42 in the following manner, as is shown in FIG. 3. An enlargement 44 is added adjacent the surface 22 of the head end aperture 20. The bottom surface of the enlargement 44 will be generally semicircular providing a smooth entry for the body portion 16 of the bundling strap 10 and providing for a low stress deformance of the strap 10- within the head end aperture 20 as will be described below. Immediately adjacent the enlargement 44 is an undercut portion 46 which extends generally from the enlargement 44 to the face 24. The lower aperture defining surface 42 is modified so as to provide a support 48 immediately behind the metallic tongue 32 and taking a generally inclined position as shown. The cavity 26 is then defined by the surface 50 which extends along the, and supports the, metallic tongue 32 the further surface 52 which joins the surface 28 to define the cavity 26.

The insertion of the body portion 16 of the bundling strap 10 into the aperture 20 of the head end portion 14 of FIG. 3 will cause a deflection of the metallic tongue 32 in the direction of the cavity 26, as described above with respect to FIG. 2. However, any attempt to withdraw the body portion 16 from the bundling strap 10 head end aperture 14 will cause the deflection of the metallic tongue 32 and the engagement of the body portion 16 with the enlargement 44 as is shown in FIG. 4. As is shown in FIG. 4, as a result of the attempted withdrawal of body portion 16 from the head end aperture 20 the metallic tongue 32 has been caused to deform and rests upon the support 48. The knife edge 36 of the metallic tongue 32 has been caused to bite into and engage the material of the body portion 16 of the strap 10 and has caused the body portion 16 to be pushed along the undercut portion 46 and to follow generally the contour of the enlargement 44. Due to the arrangement of the enlargement 44 and the undercut portion 46, as well as the backup support 48, the strap body portion 16 Will be generally wedged in this position and will not permit further movement towards the face 22 of the metallic tongue 32.

It has been found in practice that it is not necessary for the bottom surface of the enlargement 44 to be uniform along its entire Width, it may vary such as to provide cutout areas, serrations or similar surfaces for engaging with the surface of the body portion 16. In addition, although a single metallic tongue 32 has been shown, more than a single one may be provided. Further, the tongue may be plastic and molded as a part of the overall strap 10. In addition, the position of the enlargement 44 and the metallic tongue 32 may be altered or be interchanged so that the enlargement is on a bottom aperture defining surface 42 and the metallic tongue 32 extends from the upper aperture defining surface 40. In a similar fashion, the enlargement 44 may be placed adjacent face 24 and a locking means placed adjacent face 22.

While there have been shown and described and pointed out the fundamental .novel features of the invention as applied to the preferred embodiments, it will be understood that various omissions and substitutions and changes of the form and details of the devices illustrated and in their operation may be made by those skilled in the art without departing from the spirit of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A self clinching bundling strap comprising a head end portion; a tapered tail end portion; and a body portion therebetween; said head end portion having a transverse aperture therethrough for receiving therein said body portion; said transverse aperture having an upper aperture defining surface and a lower aperture defining surface; locking means mounted adjacent said lower surface and having a free end extending into said aperture to engage said body portion positioned within said aperture and an enlargement upon said upper surface whereby said free end of said locking means is prevented from moving freely in a first direction upon the attempted withdrawal of said body portion from said aperture.

2. A self clinching bundling strap, as defined in claim 1, wherein said enlargement is contoured to prevent interference by said enlargement with said body portion as same is drawn through said aperture.

3. A self clinching bundling strap, as defined in claim 1, wherein the bottom surface of said enlargement is generally semi-circular.

4. A self clinching bundling strap, as defined in claim 1, wherein said enlargement is located adjacent the entry of said transverse aperture and extends for a portion of the transverse aperture length through said head portion.

5. A self clinching bundling strap, as defined in claim 4, wherein said upper surface adjacent said enlargement and remote from the entry of said transverse aperture is undercut.

6. A self clinching bundling strap, as defined in claim 5, wherein said locking means is a metallic tongue having a knife edge at its free end and restricted to move in a second direction, the attempted withdrawal of said body portion from said aperture causing said body portion to deflect about said knife edge and generally conform to said undercut and enlargement.

7. A self clinching bundling strap, as defined in claim 1, wherein said locking means is a metallic tongue having a first end embedded in said head end portion and having a second free end extending into said transverse aperture.

8. A self clinching bundling strap, as defined in claim 7, further comprising a support member on said lower surface, said support member in engagement with said 5 6 metallic tongue to limit said tongues movement in a portion being forced into engagement with said enlargefirst direction. ment and said support member.

9. A self clinching bundling strap, as defined in claim 8, further comprising a cavity in said lower surface adf rences Cited jacent said metallic tongue, to permit said tongue to r UNITED STATES PATENTS freely move in a second direction, opposite said first direction; when said body portion is inserted in said trans- 3106028 10/1963 Baumgarmer' verse aperture; said tongue being limited from moving in 3,186,047 6/1965 SehWeStel et said first direction due to an attempt to withdraw the 3,224,056 12/1965 Joffc.

body portion, by the combined effects of the free end 10 of said tongue engaging said body portion, said body DONALD A. GRIFFIN, Primary Examiner 

